Promised many times and repeatedly delayed, Cossacks 3 [Steam] is now officially in open beta for all Linux gamers.
The great news is that the online gameplay is compatible with Windows!
The game seemed to work pretty well when I last tried it during the closed beta on Nvidia. On AMD it's possible it may have issues, as editor BTRE has been unable to run it.
See the full announcement here for further information.
I'm really pleased they are a developer we can keep in our good books for really trying their best to deliver the Linux version.
We will have much more thorough thoughts available when it leaves beta.